deps: update rustls v0.20.1 -> v0.21.0

This commit updates hyper-rustls to use the freshly released rustls
0.21.0.work.

We also use a patch to pick up a WIP upgrade[0] to tokio-rustls to match
rustls versions there.

[0]: tokio-rs/tls#137

Cargo.toml

@@ -14,15 +14,15 @@ http = "0.2"
 hyper = { version = "0.14", default-features = false, features = ["client"] }
 log = { version = "0.4.4", optional = true }
 rustls-native-certs = { version = "0.6", optional = true }
-rustls = { version = "0.20.1", default-features = false }
+rustls = { version = "0.21.0", default-features = false }
 tokio = "1.0"
-tokio-rustls = { version = "0.23", default-features = false }
+tokio-rustls = { version = "0.24.0", default-features = false }
 webpki-roots = { version = "0.22", optional = true }
 
 [dev-dependencies]
 futures-util = { version = "0.3.1", default-features = false }
 hyper = { version = "0.14", features = ["full"] }
-rustls = { version = "0.20.1", default-features = false, features = ["tls12"] }
+rustls = { version = "0.21.0", default-features = false, features = ["tls12"] }
 rustls-pemfile = "1.0.0"
 tokio = { version = "1.0", features = ["io-std", "macros", "net", "rt-multi-thread"] }
 
@@ -49,3 +49,6 @@ required-features = ["tokio-runtime"]
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
+
+[patch.crates-io]
+tokio-rustls = { git = 'https://github.com/cpu/tokio-tls', branch = 'cpu-rustls-0.21.0-prep' }